I have an O.S. .15 cv-r that I just put a new piston and cylinder. I went to break it in, and realized, hey, i dont know how to do that... before rebuild it was running around 230-250.. I know i need to richen it up, but don't know exactly where things should be set at. HSNV... Low end valve... idle i think is ok at the 1mm gap... I figured waiting a day or two is better than just trying it and leaving myself with another burnt up motor.

Thanks,
Chad

Hey Steak: I have a cvr-12 in my rc10gt. The way I broke mine in was to peak it, then back off the high speed needle about 4 to 500 rpm, and drive it. Don't hammer the throttle for about 4 to 5 tanks of fuel but don't really baby it either. After running about 1 gallon of fuel through it you can begin to lean it out to about 200 rpm off peak. For the low speed needle, I just play with it until I get instant, good smooth, throttle transition. Mine runs like there is no tomorrow I love it! Now if I could just get it to like the clutch bearings that I have to replace about every 10th run. You might wan't to go into the car forum and chat with some of those folks, they would probably be more help than I. I'm more into planes but I'm alway glad to help if I can. Garry

Thanks for the helpful yet vague information I'm on my third tank now... running it rich enough that it just barely starts... i guess after the 4th i'll start to lean out the bottom end a little.. O.S contradicts themselves saying in the manual to run 2 tanks through witht the car off the ground... but on the website it says to start driving immediately... which way do you guys do it?

Hi again steak: Sorry about the vague answer I'm not sure what you mean by that. I can tell you that I run the high speed needle at between 1 1/2 and 2 turns open, it vary's from day to day or even if the weather changes, or a multitude of other scenario's. Also it will change from engine to engine. The low speed needle is about flush with the throttle arm, again it will vary. You do not wan't to break it in to rich. ABC engines have to get up to operating temp. for the piston to seat in the cyl. properly. I say peak it and then back off about 4 to 500 rpm during break in. This has to be done pretty much by ear to the best of my knowledge, unless someone makes a tack. for cars, I really don't know. The only reason I can think of why the instructions would say to break it in with the wheels off the ground, would be if the car was new as well. IMHO the car takes more time to break in than the engine. If things are still tight in the drive train, the engine has to work that much harder to turn everything and causes it to get hot, I'm sure I don't have to say that's NOT GOOD! Just remember that it is not good to run them to rich either. You may wan't to go to a site called rcfaq.com It has some really good info about engines. It refers mainly to air plane engines, but for ABC engines the break in procedure is pretty much the same. Other than that the guys/girls in the car forum might be able to help more than I can, but I hope this helped you out a little more. Always glad to help if I can. Garry